 | |
| Paradigms | Multi-paradigm:procedural,imperative,structured,object-oriented |
|---|---|
| Family | ALGOL |
| Designed by | Ole-Johan Dahl |
| Developer | Kristen Nygaard |
| First appeared | 1962; 63 years ago (1962) |
| Stable release | Simula 67, Simula I |
| Typing discipline | Static,nominative |
| Scope | Lexical |
| Implementation language | ALGOL 60 (mostly) SIMSCRIPT (some parts) |
| OS | Unix-like,Windows,z/OS,TOPS-10,MVS |
| Website | www |
| Influenced by | |
| ALGOL 60,SIMSCRIPT | |
| Influenced | |
| BETA,CLU,Eiffel,Emerald,Pascal,Smalltalk,C++, and many otherobject-oriented programming languages | |
Simula is the name of twosimulationprogramming languages, Simula I and Simula 67, developed in the 1960s at theNorwegian Computing Center inOslo, byOle-Johan Dahl andKristen Nygaard.Syntactically, it is an approximatesuperset ofALGOL 60,[1]: 1.3.1 and was also influenced by the design ofSIMSCRIPT.[2]
Simula 67 introducedobjects,[1]: 2, 5.3 classes,[1]: 1.3.3, 2 inheritance andsubclasses,[1]: 2.2.1 virtual procedures,[1]: 2.2.3 coroutines,[1]: 9.2 anddiscrete event simulation,[1]: 14.2 and featuredgarbage collection.[1]: 9.1 Other forms ofsubtyping (besides inheriting subclasses) were introduced in Simula derivatives.[citation needed]
Simula is considered thefirst object-oriented programming language. As its name suggests, the first Simula version by 1962 was designed for doingsimulations; Simula 67 though was designed to be a general-purpose programming language[3] and provided the framework for many of the features of object-oriented languages today.
Simula has been used in a wide range of applications such as simulatingvery-large-scale integration (VLSI) designs,process modeling,communication protocols,algorithms, and other applications such astypesetting,computer graphics, andeducation.
Computer scientists such asBjarne Stroustrup, creator of C++, andJames Gosling, creator of Java, have acknowledged Simula as a major influence.[4] Simula-type objects are reimplemented inC++,Object Pascal,Java,C#, and many other languages.
The following account is based on Jan Rune Holmevik's historical essay.[5][6]
Kristen Nygaard started writing computer simulation programs in 1957. Nygaard saw a need for a better way to describe the heterogeneity and theoperation of a system. To go further with his ideas on aformalcomputer language for describing a system, Nygaard realized that he needed someone with morecomputer programming skills than he had.Ole-Johan Dahl joined him on his work in January 1962. The decision of linking the language up toALGOL 60 was made shortly after. By May 1962, the main concepts for asimulationlanguage were set.SIMULA I was born, a special purpose programming language for simulating discrete event systems.
Kristen Nygaard was invited to visit theEckert–Mauchly Computer Corporation in late May 1962 in connection with the marketing of their newUNIVAC 1107 computer. At that visit, Nygaard presented the ideas of Simula toRobert Bemer, the director of systems programming atUnivac. Bemer was a greatALGOL fan and found the Simula project compelling. Bemer was alsochairperson of a session at the second international conference on information processing hosted byInternational Federation for Information Processing (IFIP). He invited Nygaard, who presented the paper "SIMULA – An Extension of ALGOL to the Description of Discrete-Event Networks".
TheNorwegian Computing Center got aUNIVAC 1107 in August 1963 at a considerable discount, on which Dahl implemented the SIMULA I under contract with UNIVAC. The implementation was based on the UNIVACALGOL 60 compiler. SIMULA I was fully operational on the UNIVAC 1107 by January 1965. In the following few years, Dahl and Nygaard spent a lot of time teaching Simula. Simula spread to several countries around the world and SIMULA I was later implemented on other computers including theBurroughs B5500 and the RussianUral-16.
In 1966C. A. R. Hoare introduced the concept of record class construct, which Dahl and Nygaard extended with the concept of prefixing and other features to meet their requirements for a generalized process concept. Dahl and Nygaard presented their paper onClass andSubclass declarations at the IFIP Working Conference onsimulation languages inOslo, May 1967. This paper became the first formal definition of Simula 67. In June 1967, a conference was held to standardize the language and initiate a number of implementations. Dahl proposed to unify thetype and the class concept. This led to serious discussions, and the proposal was rejected by the board. Simula 67 was formally standardized on the first meeting of the Simula Standards Group (SSG) in February 1968.
Simula was influential in the development ofSmalltalk and laterobject-oriented programming languages. It also helped inspire theactor model of concurrent computation although Simula only supportscoroutines and not trueconcurrency.[7]
In the late sixties and the early seventies, there were four main implementations of Simula:
These implementations were ported to a wide range of platforms. TheTOPS-10 implemented the concept of public, protected, and private member variables and procedures, that later was integrated into Simula Standard in 1986.
Simula Standard 1986 is the latest standard and is ported to a wide range of platforms. There are mainly four implementations:
In November 2001, Dahl and Nygaard were awarded theIEEE John von Neumann Medal by theInstitute of Electrical and Electronics Engineers "For the introduction of the concepts underlying object-oriented programming through the design and implementation of SIMULA 67". In April 2002, they received the 2001 A. M.Turing Award by theAssociation for Computing Machinery (ACM), with the citation: "For ideas fundamental to the emergence of object oriented programming, through their design of the programming languages Simula I and Simula 67." Dahl and Nygaard died in June and August of that year, respectively,[10] before the ACM Turing Award Lecture[11] that was scheduled to be delivered at the November 2002OOPSLA conference in Seattle.
Simula Research Laboratory is aresearch institute named after the Simula language, and Nygaard held a part-time position there from the opening in 2001. The new Computer Science building at theUniversity of Oslo is named Ole Johan Dahl's House, in Dahl's honour, and the main auditorium is named Simula.
The development of .. SIMULA I and SIMULA 67... were influenced by the design of SIMSCRIPT ...
| International | |
|---|---|
| National | |
